//! Generic Case A LoopForm → JoinIR lowering (v1, minimal_ssa_skip_ws 専用)
//!
//! 制約（必読）:
//! - 条件式の中身を解析しない（Compare/BinOp を MIR そのままコピーするだけ）
//! - 多重ヘッダ/ネストループは対象外（v1 は minimal_ssa_skip_ws の単純ループ専用）
//! - pinned/carrier/exit は LoopVarClassBox / LoopExitLivenessBox から渡された前提で扱う
//! - 解析に失敗したら必ず None を返し、呼び元にフォールバックさせる

use std::collections::BTreeMap;

use crate::mir::join_ir::lowering::loop_scope_shape::CaseAContext;
use crate::mir::join_ir::lowering::value_id_ranges;
use crate::mir::join_ir::lowering::value_id_ranges::skip_ws as vid;
use crate::mir::join_ir::lowering::value_id_ranges::stage1_using_resolver as stage1_vid;
use crate::mir::join_ir::{
    BinOpKind, CompareOp, ConstValue, JoinContId, JoinFuncId, JoinFunction, JoinInst, JoinModule,
    LoopExitShape, LoopHeaderShape, MirLikeInst,
};
use crate::mir::loop_form::LoopForm;
use crate::mir::phi_core::loop_exit_liveness::LoopExitLivenessBox;
use crate::mir::phi_core::loop_var_classifier::LoopVarClassBox;
use crate::mir::{MirFunction, MirQuery, ValueId};

/// v1: minimal_ssa_skip_ws 専用の汎用 Case A ロワー
///
/// - LoopForm / VarClass / ExitLiveness は形の検証にのみ使う（パターンが合わなければ None）
/// - JoinModule の形は hand-written skip_ws と同一になるように組み立てる
pub fn lower_case_a_loop_to_joinir_for_minimal_skip_ws(
    loop_form: &LoopForm,
    var_classes: &LoopVarClassBox,
    exit_live: &LoopExitLivenessBox,
    query: &impl MirQuery,
    mir_func: &MirFunction,
) -> Option<JoinModule> {
    // 追加の latch チェック（skip_ws 固有）
    if loop_form.latch != loop_form.body && loop_form.latch != loop_form.header {
        eprintln!(
            "[joinir/generic_case_a] unexpected latch {:?} (body={:?}, header={:?}), fallback",
            loop_form.latch, loop_form.body, loop_form.header
        );
        return None;
    }

    // CaseAContext で共通ロジックを実行
    let ctx = CaseAContext::new(
        loop_form,
        var_classes,
        exit_live,
        query,
        mir_func,
        "skip_ws",
        |offset| vid::loop_step(offset),
    )?;

    // JoinModule を手書き skip_ws と同じ形で構築（ValueId 範囲も揃える）
    let string_key = ctx.pinned_name_or_first(0)?;
    let len_key = ctx.pinned_name_or_first(1).unwrap_or_else(|| string_key.clone());
    let index_key = ctx.carrier_name_or_first(0)?;

    let s_loop = ctx.get_loop_id(&string_key)?;
    let i_loop = ctx.get_loop_id(&index_key)?;
    let n_loop = ctx.get_loop_id(&len_key)?;

    let mut join_module = JoinModule::new();

    // entry: skip(s)
    let skip_id = JoinFuncId::new(0);
    let s_param = vid::entry(0); // 3000
    let mut skip_func = JoinFunction::new(skip_id, "skip".to_string(), vec![s_param]);

    let i_init = vid::entry(1); // 3001
    let n_val = vid::entry(2); // 3002

    let mut entry_name_to_id: BTreeMap<String, ValueId> = BTreeMap::new();
    entry_name_to_id.insert(string_key.clone(), s_param);
    entry_name_to_id.insert(index_key.clone(), i_init);
    entry_name_to_id.insert(len_key.clone(), n_val);

    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: i_init,
        value: ConstValue::Integer(0),
    }));

    skip_func.body.push(JoinInst::Compute(MirLikeInst::BoxCall {
        dst: Some(n_val),
        box_name: "StringBox".to_string(),
        method: "length".to_string(),
        args: vec![s_param],
    }));

    let loop_step_id = JoinFuncId::new(1);
    let loop_call_args: Vec<ValueId> = ctx
        .ordered_pinned
        .iter()
        .chain(ctx.ordered_carriers.iter())
        .map(|name| entry_name_to_id.get(name).copied())
        .collect::<Option<_>>()?;

    skip_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: loop_call_args,
        k_next: None,
        dst: None,
    });

    join_module.entry = Some(skip_id);
    join_module.add_function(skip_func);

    // loop_step(s, i, n)
    let header_shape = LoopHeaderShape::new_manual(ctx.pinned_ids.clone(), ctx.carrier_ids.clone());
    let loop_params = header_shape.to_loop_step_params();
    let mut loop_step_func =
        JoinFunction::new(loop_step_id, "loop_step".to_string(), loop_params.clone());

    let cmp1_result = vid::loop_step(3); // 4003
    let ch = vid::loop_step(4); // 4004
    let cmp2_result = vid::loop_step(5); // 4005
    let i_plus_1 = vid::loop_step(6); // 4006
    let const_1 = vid::loop_step(7); // 4007
    let const_space = vid::loop_step(10); // 4010
    let bool_false = vid::loop_step(11); // 4011
    let cmp2_is_false = vid::loop_step(12); // 4012

    // cmp1_result = (i >= n)
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp1_result,
            op: CompareOp::Ge,
            lhs: i_loop,
            rhs: n_loop,
        }));

    let _exit_shape = if ctx.exit_args.is_empty() {
        LoopExitShape::new_manual(vec![i_loop])
    } else {
        LoopExitShape::new_manual(ctx.exit_args.clone())
    }; // exit_args = [i] が期待値

    // if i >= n { return i }
    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(0),
        args: vec![i_loop],
        cond: Some(cmp1_result),
    });

    // const 1
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_1,
            value: ConstValue::Integer(1),
        }));

    // i_plus_1 = i + 1
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: i_plus_1,
            op: BinOpKind::Add,
            lhs: i_loop,
            rhs: const_1,
        }));

    // ch = s.substring(i, i + 1)
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(ch),
            box_name: "StringBox".to_string(),
            method: "substring".to_string(),
            args: vec![s_loop, i_loop, i_plus_1],
        }));

    // const " "
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_space,
            value: ConstValue::String(" ".to_string()),
        }));

    // cmp2_result = (ch == " ")
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp2_result,
            op: CompareOp::Eq,
            lhs: ch,
            rhs: const_space,
        }));

    // bool false
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: bool_false,
            value: ConstValue::Bool(false),
        }));

    // cmp2_is_false = (cmp2_result == false)
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp2_is_false,
            op: CompareOp::Eq,
            lhs: cmp2_result,
            rhs: bool_false,
        }));

    // if ch != " " { return i }
    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(1),
        args: vec![i_loop],
        cond: Some(cmp2_is_false),
    });

    // continue: loop_step(s, i+1, n)
    loop_step_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: vec![s_loop, i_plus_1, n_loop],
        k_next: None,
        dst: None,
    });

    join_module.add_function(loop_step_func);

    eprintln!(
        "[joinir/generic_case_a] ✅ constructed JoinIR (functions={}, value_range={}..{})",
        join_module.functions.len(),
        value_id_ranges::base::SKIP_WS,
        value_id_ranges::base::SKIP_WS + 1999
    );

    Some(join_module)
}

/// Placeholder: trim minimal 用の generic Case A ロワー（v0, 未実装）
///
/// - いまは構造チェックのみで必ず None を返し、呼び元でフォールバックさせる
/// - 将来 trim_minimal を generic_case_a で置き換える際の導線として用意
pub fn lower_case_a_loop_to_joinir_for_trim_minimal(
    loop_form: &LoopForm,
    var_classes: &LoopVarClassBox,
    exit_live: &LoopExitLivenessBox,
    query: &impl MirQuery,
    mir_func: &MirFunction,
) -> Option<JoinModule> {
    // CaseAContext で共通ロジックを実行
    let ctx = CaseAContext::new(
        loop_form,
        var_classes,
        exit_live,
        query,
        mir_func,
        "trim",
        |offset| value_id_ranges::funcscanner_trim::loop_step(offset),
    )?;

    let string_key = ctx.pinned_name_or_first(0)?;
    let base_key = ctx.pinned_name_or_first(1).unwrap_or_else(|| string_key.clone());
    let carrier_key = ctx.carrier_name_or_first(0)?;

    let s_loop = ctx.get_loop_id(&string_key)?;
    let b_loop = ctx.get_loop_id(&base_key)?;
    let e_loop = ctx.get_loop_id(&carrier_key)?;

    let mut join_module = JoinModule::new();

    // entry: trim_main(s_param)
    let trim_main_id = JoinFuncId::new(0);
    let s_param = value_id_ranges::funcscanner_trim::entry(0);
    let mut trim_main_func =
        JoinFunction::new(trim_main_id, "trim_main".to_string(), vec![s_param]);

    let str_val = value_id_ranges::funcscanner_trim::entry(1);
    let n_val = value_id_ranges::funcscanner_trim::entry(2);
    let b_val = value_id_ranges::funcscanner_trim::entry(3);
    let e_init = value_id_ranges::funcscanner_trim::entry(4);
    let const_empty = value_id_ranges::funcscanner_trim::entry(5);
    let const_zero = value_id_ranges::funcscanner_trim::entry(6);

    trim_main_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_empty,
            value: ConstValue::String("".to_string()),
        }));
    trim_main_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: str_val,
            lhs: const_empty,
            rhs: s_param,
            op: BinOpKind::Add,
        }));
    trim_main_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(n_val),
            box_name: "StringBox".to_string(),
            method: "length".to_string(),
            args: vec![str_val],
        }));
    trim_main_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_zero,
            value: ConstValue::Integer(0),
        }));

    let skip_leading_id = JoinFuncId::new(2);
    trim_main_func.body.push(JoinInst::Call {
        func: skip_leading_id,
        args: vec![str_val, const_zero, n_val],
        k_next: None,
        dst: Some(b_val),
    });

    trim_main_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: e_init,
            op: BinOpKind::Add,
            lhs: n_val,
            rhs: const_zero,
        }));

    let mut entry_name_to_id: BTreeMap<String, ValueId> = BTreeMap::new();
    entry_name_to_id.insert(string_key.clone(), str_val);
    entry_name_to_id.insert(base_key.clone(), b_val);
    entry_name_to_id.insert(carrier_key.clone(), e_init);

    let loop_call_args: Vec<ValueId> = ctx
        .ordered_pinned
        .iter()
        .chain(ctx.ordered_carriers.iter())
        .map(|name| entry_name_to_id.get(name).copied())
        .collect::<Option<_>>()?;

    let loop_step_id = JoinFuncId::new(1);
    trim_main_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: loop_call_args,
        k_next: None,
        dst: None,
    });

    join_module.entry = Some(trim_main_id);
    join_module.add_function(trim_main_func);

    // loop_step(str, b, e)
    let header_shape = LoopHeaderShape::new_manual(ctx.pinned_ids.clone(), ctx.carrier_ids.clone());
    let loop_params = header_shape.to_loop_step_params();
    let mut loop_step_func =
        JoinFunction::new(loop_step_id, "loop_step".to_string(), loop_params.clone());

    let cond = value_id_ranges::funcscanner_trim::loop_step(3);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cond,
            lhs: e_loop,
            rhs: b_loop,
            op: CompareOp::Gt,
        }));

    let bool_false = value_id_ranges::funcscanner_trim::loop_step(19);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: bool_false,
            value: ConstValue::Bool(false),
        }));

    let trimmed_base = value_id_ranges::funcscanner_trim::loop_step(4);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(trimmed_base),
            box_name: "StringBox".to_string(),
            method: "substring".to_string(),
            args: vec![s_loop, b_loop, e_loop],
        }));

    let cond_is_false = value_id_ranges::funcscanner_trim::loop_step(20);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cond_is_false,
            lhs: cond,
            rhs: bool_false,
            op: CompareOp::Eq,
        }));

    let _exit_shape_trim = if ctx.exit_args.is_empty() {
        LoopExitShape::new_manual(vec![e_loop])
    } else {
        LoopExitShape::new_manual(ctx.exit_args.clone())
    };

    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(0),
        args: vec![trimmed_base],
        cond: Some(cond_is_false),
    });

    let const_1 = value_id_ranges::funcscanner_trim::loop_step(5);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_1,
            value: ConstValue::Integer(1),
        }));

    let e_minus_1 = value_id_ranges::funcscanner_trim::loop_step(6);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: e_minus_1,
            lhs: e_loop,
            rhs: const_1,
            op: BinOpKind::Sub,
        }));

    let ch = value_id_ranges::funcscanner_trim::loop_step(7);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(ch),
            box_name: "StringBox".to_string(),
            method: "substring".to_string(),
            args: vec![s_loop, e_minus_1, e_loop],
        }));

    let cmp_space = value_id_ranges::funcscanner_trim::loop_step(8);
    let cmp_tab = value_id_ranges::funcscanner_trim::loop_step(9);
    let cmp_newline = value_id_ranges::funcscanner_trim::loop_step(10);
    let cmp_cr = value_id_ranges::funcscanner_trim::loop_step(11);

    let const_space = value_id_ranges::funcscanner_trim::loop_step(12);
    let const_tab = value_id_ranges::funcscanner_trim::loop_step(13);
    let const_newline = value_id_ranges::funcscanner_trim::loop_step(14);
    let const_cr = value_id_ranges::funcscanner_trim::loop_step(15);

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_space,
            value: ConstValue::String(" ".to_string()),
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_space,
            lhs: ch,
            rhs: const_space,
            op: CompareOp::Eq,
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_tab,
            value: ConstValue::String("\\t".to_string()),
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_tab,
            lhs: ch,
            rhs: const_tab,
            op: CompareOp::Eq,
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_newline,
            value: ConstValue::String("\\n".to_string()),
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_newline,
            lhs: ch,
            rhs: const_newline,
            op: CompareOp::Eq,
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_cr,
            value: ConstValue::String("\\r".to_string()),
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_cr,
            lhs: ch,
            rhs: const_cr,
            op: CompareOp::Eq,
        }));

    let or1 = value_id_ranges::funcscanner_trim::loop_step(16);
    let or2 = value_id_ranges::funcscanner_trim::loop_step(17);
    let is_space = value_id_ranges::funcscanner_trim::loop_step(18);

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: or1,
            lhs: cmp_space,
            rhs: cmp_tab,
            op: BinOpKind::Or,
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: or2,
            lhs: or1,
            rhs: cmp_newline,
            op: BinOpKind::Or,
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: is_space,
            lhs: or2,
            rhs: cmp_cr,
            op: BinOpKind::Or,
        }));

    let is_space_false = value_id_ranges::funcscanner_trim::loop_step(21);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: is_space_false,
            lhs: is_space,
            rhs: bool_false,
            op: CompareOp::Eq,
        }));

    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(1),
        args: vec![trimmed_base],
        cond: Some(is_space_false),
    });

    let e_next = value_id_ranges::funcscanner_trim::loop_step(22);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: e_next,
            lhs: e_loop,
            rhs: const_1,
            op: BinOpKind::Sub,
        }));

    loop_step_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: vec![s_loop, b_loop, e_next],
        k_next: None,
        dst: None,
    });

    join_module.add_function(loop_step_func);

    // skip_leading 関数（共通ロジックを手書き版と合わせる）
    let mut skip_func = JoinFunction::new(
        skip_leading_id,
        "skip_leading".to_string(),
        vec![ValueId(7000), ValueId(7001), ValueId(7002)],
    );
    let s_skip = ValueId(7000);
    let i_skip = ValueId(7001);
    let n_skip = ValueId(7002);
    let cmp_len = ValueId(7003);
    let const_1_skip = ValueId(7004);
    let i_plus_1_skip = ValueId(7005);
    let ch_skip = ValueId(7006);
    let cmp_space_skip = ValueId(7007);
    let cmp_tab_skip = ValueId(7008);
    let cmp_newline_skip = ValueId(7009);
    let cmp_cr_skip = ValueId(7010);
    let const_space_skip = ValueId(7011);
    let const_tab_skip = ValueId(7012);
    let const_newline_skip = ValueId(7013);
    let const_cr_skip = ValueId(7014);
    let or1_skip = ValueId(7015);
    let or2_skip = ValueId(7016);
    let is_space_skip = ValueId(7017);
    let bool_false_skip = ValueId(7018);
    let is_space_false_skip = ValueId(7019);

    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: cmp_len,
        lhs: i_skip,
        rhs: n_skip,
        op: CompareOp::Ge,
    }));
    skip_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(2),
        args: vec![i_skip],
        cond: Some(cmp_len),
    });
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: const_1_skip,
        value: ConstValue::Integer(1),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::BinOp {
        dst: i_plus_1_skip,
        lhs: i_skip,
        rhs: const_1_skip,
        op: BinOpKind::Add,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::BoxCall {
        dst: Some(ch_skip),
        box_name: "StringBox".to_string(),
        method: "substring".to_string(),
        args: vec![s_skip, i_skip, i_plus_1_skip],
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: const_space_skip,
        value: ConstValue::String(" ".to_string()),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: cmp_space_skip,
        lhs: ch_skip,
        rhs: const_space_skip,
        op: CompareOp::Eq,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: const_tab_skip,
        value: ConstValue::String("\\t".to_string()),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: cmp_tab_skip,
        lhs: ch_skip,
        rhs: const_tab_skip,
        op: CompareOp::Eq,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: const_newline_skip,
        value: ConstValue::String("\\n".to_string()),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: cmp_newline_skip,
        lhs: ch_skip,
        rhs: const_newline_skip,
        op: CompareOp::Eq,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: const_cr_skip,
        value: ConstValue::String("\\r".to_string()),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: cmp_cr_skip,
        lhs: ch_skip,
        rhs: const_cr_skip,
        op: CompareOp::Eq,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::BinOp {
        dst: or1_skip,
        lhs: cmp_space_skip,
        rhs: cmp_tab_skip,
        op: BinOpKind::Or,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::BinOp {
        dst: or2_skip,
        lhs: or1_skip,
        rhs: cmp_newline_skip,
        op: BinOpKind::Or,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::BinOp {
        dst: is_space_skip,
        lhs: or2_skip,
        rhs: cmp_cr_skip,
        op: BinOpKind::Or,
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: bool_false_skip,
        value: ConstValue::Bool(false),
    }));
    skip_func.body.push(JoinInst::Compute(MirLikeInst::Compare {
        dst: is_space_false_skip,
        lhs: is_space_skip,
        rhs: bool_false_skip,
        op: CompareOp::Eq,
    }));
    skip_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(3),
        args: vec![i_skip],
        cond: Some(is_space_false_skip),
    });
    skip_func.body.push(JoinInst::Call {
        func: skip_leading_id,
        args: vec![s_skip, i_plus_1_skip, n_skip],
        k_next: None,
        dst: None,
    });

    join_module.add_function(skip_func);

    eprintln!(
        "[joinir/generic_case_a/trim] ✅ constructed JoinIR (functions={}, value_range={}..{})",
        join_module.functions.len(),
        value_id_ranges::base::FUNCSCANNER_TRIM,
        value_id_ranges::base::FUNCSCANNER_TRIM + 1999
    );

    Some(join_module)
}

/// append_defs_minimal 用の generic Case A ロワー（LoopForm/VarClass/ExitLiveness ベース）
///
/// - LoopForm が単一 header/latch でない場合や、必要な変数がマッピングできない場合は None を返す。
/// - 既存の手書き JoinIR（append_defs_entry + loop_step）と同じ形を目指す。
pub fn lower_case_a_loop_to_joinir_for_append_defs_minimal(
    loop_form: &LoopForm,
    var_classes: &LoopVarClassBox,
    exit_live: &LoopExitLivenessBox,
    query: &impl MirQuery,
    mir_func: &MirFunction,
) -> Option<JoinModule> {
    // CaseAContext で共通ロジックを実行
    let ctx = CaseAContext::new(
        loop_form,
        var_classes,
        exit_live,
        query,
        mir_func,
        "append_defs",
        |offset| value_id_ranges::funcscanner_append_defs::loop_step(offset),
    )?;

    let dst_key = ctx.pinned_name_or_first(0)?;
    let defs_key = ctx.pinned_name_or_first(1).unwrap_or_else(|| dst_key.clone());
    let n_key = ctx.pinned_name_or_first(2).unwrap_or_else(|| defs_key.clone());
    let i_key = ctx.carrier_name_or_first(0)?;

    let dst_loop = ctx.get_loop_id(&dst_key)?;
    let defs_loop = ctx.get_loop_id(&defs_key)?;
    let n_loop = ctx.get_loop_id(&n_key)?;
    let i_loop = ctx.get_loop_id(&i_key)?;

    let mut join_module = JoinModule::new();

    // entry: append_defs_entry(dst, defs_box, n)
    let entry_id = JoinFuncId::new(0);
    let dst_param = value_id_ranges::funcscanner_append_defs::entry(0);
    let defs_box_param = value_id_ranges::funcscanner_append_defs::entry(1);
    let n_param = value_id_ranges::funcscanner_append_defs::entry(2);
    let mut entry_func = JoinFunction::new(
        entry_id,
        "append_defs_entry".to_string(),
        vec![dst_param, defs_box_param, n_param],
    );

    let i_init = value_id_ranges::funcscanner_append_defs::entry(10);
    entry_func.body.push(JoinInst::Compute(MirLikeInst::Const {
        dst: i_init,
        value: ConstValue::Integer(0),
    }));
    let mut entry_name_to_id: BTreeMap<String, ValueId> = BTreeMap::new();
    entry_name_to_id.insert("s".to_string(), dst_param); // intake で param0 を "s" にするため
    entry_name_to_id.insert("dst".to_string(), dst_param);
    entry_name_to_id.insert("param1".to_string(), defs_box_param);
    entry_name_to_id.insert("defs_box".to_string(), defs_box_param);
    entry_name_to_id.insert("n".to_string(), n_param);
    entry_name_to_id.insert("i".to_string(), i_init);

    let loop_call_args: Vec<ValueId> = ctx
        .ordered_pinned
        .iter()
        .chain(ctx.ordered_carriers.iter())
        .map(|name| entry_name_to_id.get(name).copied())
        .collect::<Option<_>>()?;

    let loop_step_id = JoinFuncId::new(1);
    entry_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: loop_call_args,
        k_next: None,
        dst: None,
    });

    join_module.entry = Some(entry_id);
    join_module.add_function(entry_func);

    // loop_step(dst, defs_box, n, i)
    let header_shape = LoopHeaderShape::new_manual(ctx.pinned_ids.clone(), ctx.carrier_ids.clone());
    let loop_params = header_shape.to_loop_step_params();
    let mut loop_step_func =
        JoinFunction::new(loop_step_id, "loop_step".to_string(), loop_params.clone());

    let cmp_result = value_id_ranges::funcscanner_append_defs::loop_step(10);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_result,
            op: CompareOp::Ge,
            lhs: i_loop,
            rhs: n_loop,
        }));

    let _exit_shape = LoopExitShape::new_manual(ctx.exit_args.clone());

    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(0),
        args: ctx.exit_args.clone(),
        cond: Some(cmp_result),
    });

    let item_value = value_id_ranges::funcscanner_append_defs::loop_step(11);
    let next_i = value_id_ranges::funcscanner_append_defs::loop_step(12);
    let const_1 = value_id_ranges::funcscanner_append_defs::loop_step(13);

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(item_value),
            box_name: "ArrayBox".to_string(),
            method: "get".to_string(),
            args: vec![defs_loop, i_loop],
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: None,
            box_name: "ArrayBox".to_string(),
            method: "push".to_string(),
            args: vec![dst_loop, item_value],
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_1,
            value: ConstValue::Integer(1),
        }));

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: next_i,
            op: BinOpKind::Add,
            lhs: i_loop,
            rhs: const_1,
        }));

    loop_step_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: vec![dst_loop, defs_loop, n_loop, next_i],
        k_next: None,
        dst: None,
    });

    join_module.add_function(loop_step_func);

    eprintln!(
        "[joinir/generic_case_a/append_defs] ✅ constructed JoinIR (functions={}, value_range={}..{})",
        join_module.functions.len(),
        value_id_ranges::base::FUNCSCANNER_APPEND_DEFS,
        value_id_ranges::base::FUNCSCANNER_APPEND_DEFS + 1999
    );

    Some(join_module)
}

/// Stage1UsingResolver minimal 用の generic Case A ロワー（LoopForm/VarClass/ExitLiveness ベース）
pub fn lower_case_a_loop_to_joinir_for_stage1_usingresolver_minimal(
    loop_form: &LoopForm,
    var_classes: &LoopVarClassBox,
    exit_live: &LoopExitLivenessBox,
    query: &impl MirQuery,
    mir_func: &MirFunction,
) -> Option<JoinModule> {
    // CaseAContext で共通ロジックを実行
    let ctx = CaseAContext::new(
        loop_form,
        var_classes,
        exit_live,
        query,
        mir_func,
        "stage1",
        |offset| stage1_vid::loop_step(offset),
    )?;

    let entries_key = ctx.pinned_name_or_first(0)?;
    let n_key = ctx.pinned_name_or_first(1).unwrap_or_else(|| entries_key.clone());
    let modules_key = ctx.pinned_name_or_first(2).unwrap_or_else(|| entries_key.clone());
    let seen_key = ctx.pinned_name_or_first(3).unwrap_or_else(|| entries_key.clone());
    let prefix_key = ctx.carrier_name_or_first(0)?;
    let i_key = ctx.carrier_name_or_first(1).unwrap_or_else(|| prefix_key.clone());

    let entries_loop = ctx.get_loop_id(&entries_key)?;
    let n_loop = ctx.get_loop_id(&n_key)?;
    let modules_loop = ctx.get_loop_id(&modules_key)?;
    let seen_loop = ctx.get_loop_id(&seen_key)?;
    let prefix_loop = ctx.get_loop_id(&prefix_key)?;
    let i_loop = ctx.get_loop_id(&i_key)?;

    let mut join_module = JoinModule::new();

    // entry: resolve_entries(entries, n, modules, seen, prefix_init)
    let resolve_id = JoinFuncId::new(0);
    let entries_param = stage1_vid::entry(0);
    let n_param = stage1_vid::entry(1);
    let modules_param = stage1_vid::entry(2);
    let seen_param = stage1_vid::entry(3);
    let prefix_param = stage1_vid::entry(4);
    let mut resolve_func = JoinFunction::new(
        resolve_id,
        "resolve_entries".to_string(),
        vec![
            entries_param,
            n_param,
            modules_param,
            seen_param,
            prefix_param,
        ],
    );

    let i_init = stage1_vid::entry(10);
    resolve_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: i_init,
            value: ConstValue::Integer(0),
        }));

    let mut entry_name_to_id: BTreeMap<String, ValueId> = BTreeMap::new();
    entry_name_to_id.insert(entries_key.clone(), entries_param);
    entry_name_to_id.insert(n_key.clone(), n_param);
    entry_name_to_id.insert(modules_key.clone(), modules_param);
    entry_name_to_id.insert(seen_key.clone(), seen_param);
    entry_name_to_id.insert(prefix_key.clone(), prefix_param);
    entry_name_to_id.insert(i_key.clone(), i_init);

    let loop_call_args: Vec<ValueId> = ctx
        .ordered_pinned
        .iter()
        .chain(ctx.ordered_carriers.iter())
        .map(|name| entry_name_to_id.get(name).copied())
        .collect::<Option<_>>()?;

    let loop_step_id = JoinFuncId::new(1);
    resolve_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: loop_call_args,
        k_next: None,
        dst: None,
    });

    join_module.entry = Some(resolve_id);
    join_module.add_function(resolve_func);

    // loop_step(entries, n, modules, seen, prefix, i)
    let header_shape = LoopHeaderShape::new_manual(ctx.pinned_ids.clone(), ctx.carrier_ids.clone());
    let loop_params = header_shape.to_loop_step_params();
    let mut loop_step_func =
        JoinFunction::new(loop_step_id, "loop_step".to_string(), loop_params.clone());

    let cmp_result = stage1_vid::loop_step(10);
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Compare {
            dst: cmp_result,
            op: CompareOp::Ge,
            lhs: i_loop,
            rhs: n_loop,
        }));

    let exit_shape = if ctx.exit_args.is_empty() {
        LoopExitShape::new_manual(vec![prefix_loop])
    } else {
        LoopExitShape::new_manual(ctx.exit_args.clone())
    };

    loop_step_func.body.push(JoinInst::Jump {
        cont: JoinContId::new(0),
        args: exit_shape.exit_args.clone(),
        cond: Some(cmp_result),
    });

    let entry_value = stage1_vid::loop_step(11);
    let next_i = stage1_vid::loop_step(12);
    let const_1 = stage1_vid::loop_step(13);
    let new_prefix = stage1_vid::loop_step(14);

    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BoxCall {
            dst: Some(entry_value),
            box_name: "ArrayBox".to_string(),
            method: "get".to_string(),
            args: vec![entries_loop, i_loop],
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::Const {
            dst: const_1,
            value: ConstValue::Integer(1),
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: next_i,
            op: BinOpKind::Add,
            lhs: i_loop,
            rhs: const_1,
        }));
    loop_step_func
        .body
        .push(JoinInst::Compute(MirLikeInst::BinOp {
            dst: new_prefix,
            op: BinOpKind::Or,
            lhs: prefix_loop,
            rhs: entry_value,
        }));
    loop_step_func.body.push(JoinInst::Call {
        func: loop_step_id,
        args: vec![
            entries_loop,
            n_loop,
            modules_loop,
            seen_loop,
            new_prefix,
            next_i,
        ],
        k_next: None,
        dst: None,
    });

    join_module.add_function(loop_step_func);

    eprintln!(
        "[joinir/generic_case_a/stage1] ✅ constructed JoinIR (functions={}, value_range={}..{})",
        join_module.functions.len(),
        value_id_ranges::base::STAGE1_USING_RESOLVER,
        value_id_ranges::base::STAGE1_USING_RESOLVER + 1999
    );

    Some(join_module)
}