#![cfg(feature = "normalized_dev")]

use crate::config::env::joinir_dev_enabled;
use crate::mir::join_ir::normalized::dev_env;
use crate::mir::join_ir::{JoinFuncId, JoinFunction, JoinInst, JoinModule};

/// Phase 44: Shape capability kinds (capability-based routing)
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ShapeCapabilityKind {
    /// P2 Core: Simple mini patterns (i/acc/n etc)
    P2CoreSimple,

    /// P2 Core: skip_whitespace mini/real
    P2CoreSkipWs,

    /// P2 Core: _atoi mini/real
    P2CoreAtoi,

    /// P2 Mid: _parse_number real (p + num_str + result)
    P2MidParseNumber,

    // Future: Other P2 patterns
    // P2MidAtOfLoop,
    // P2HeavyString,
}

/// Phase 44: Shape capability descriptor
#[derive(Debug, Clone)]
pub struct ShapeCapability {
    pub kind: ShapeCapabilityKind,
    // Future extensibility fields (not all used yet):
    // pub pattern_kind: LoopPatternKind,
    // pub loop_param_count: usize,
    // pub carrier_roles: Vec<CarrierRole>,
    // pub method_calls: Vec<MethodCallSignature>,
}

impl ShapeCapability {
    pub fn new(kind: ShapeCapabilityKind) -> Self {
        Self { kind }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum NormalizedDevShape {
    Pattern1Mini,
    Pattern2Mini,
    JsonparserSkipWsMini,
    JsonparserSkipWsReal,
    JsonparserAtoiMini,
    JsonparserAtoiReal,
    JsonparserParseNumberReal,
    // Phase 47-A: Pattern3 (if-sum) minimal
    Pattern3IfSumMinimal,
}

type Detector = fn(&JoinModule) -> bool;

const SHAPE_DETECTORS: &[(NormalizedDevShape, Detector)] = &[
    (NormalizedDevShape::Pattern1Mini, detectors::is_pattern1_mini),
    (NormalizedDevShape::Pattern2Mini, detectors::is_pattern2_mini),
    (
        NormalizedDevShape::JsonparserSkipWsMini,
        detectors::is_jsonparser_skip_ws_mini,
    ),
    (
        NormalizedDevShape::JsonparserSkipWsReal,
        detectors::is_jsonparser_skip_ws_real,
    ),
    (
        NormalizedDevShape::JsonparserAtoiMini,
        detectors::is_jsonparser_atoi_mini,
    ),
    (
        NormalizedDevShape::JsonparserAtoiReal,
        detectors::is_jsonparser_atoi_real,
    ),
    (
        NormalizedDevShape::JsonparserParseNumberReal,
        detectors::is_jsonparser_parse_number_real,
    ),
    // Phase 47-A: Pattern3 if-sum minimal
    (
        NormalizedDevShape::Pattern3IfSumMinimal,
        detectors::is_pattern3_if_sum_minimal,
    ),
];

/// direct ブリッジで扱う shape（dev 限定）。
pub(crate) fn direct_shapes(module: &JoinModule) -> Vec<NormalizedDevShape> {
    let shapes = detect_shapes(module);
    log_shapes("direct", &shapes);
    shapes
}

/// Structured→Normalized の対象 shape（dev 限定）。
pub(crate) fn supported_shapes(module: &JoinModule) -> Vec<NormalizedDevShape> {
    let shapes = detect_shapes(module);
    log_shapes("roundtrip", &shapes);
    shapes
}

/// Phase 44: Map NormalizedDevShape to ShapeCapability
pub fn capability_for_shape(shape: &NormalizedDevShape) -> ShapeCapability {
    use NormalizedDevShape::*;
    use ShapeCapabilityKind::*;

    let kind = match shape {
        Pattern2Mini => P2CoreSimple,
        JsonparserSkipWsMini | JsonparserSkipWsReal => P2CoreSkipWs,
        JsonparserAtoiMini | JsonparserAtoiReal => P2CoreAtoi,
        JsonparserParseNumberReal => P2MidParseNumber,
        Pattern1Mini => P2CoreSimple, // Also core simple pattern
        // Phase 47-A: P3 minimal maps to P2CoreSimple for now (future: P3CoreSimple)
        Pattern3IfSumMinimal => P2CoreSimple,
    };

    ShapeCapability::new(kind)
}

/// Phase 46: Canonical shapes that ALWAYS use Normalized→MIR(direct)
/// regardless of feature flags or mode.
///
/// Canonical set (Phase 46):
/// - P2-Core: Pattern2Mini, JsonparserSkipWsMini, JsonparserSkipWsReal, JsonparserAtoiMini
/// - P2-Mid: JsonparserAtoiReal, JsonparserParseNumberReal
///
/// P3/P4 patterns are NOT canonical (deferred to NORM-P3/NORM-P4 phases).
pub fn is_canonical_shape(shape: &NormalizedDevShape) -> bool {
    use NormalizedDevShape::*;
    matches!(
        shape,
        Pattern2Mini
            | JsonparserSkipWsMini
            | JsonparserSkipWsReal
            | JsonparserAtoiMini
            // Phase 46: Add P2-Mid patterns
            | JsonparserAtoiReal
            | JsonparserParseNumberReal
    )
}

/// Phase 44: Check if capability kind is in P2-Core family
///
/// This checks capability-level membership, not granular canonical status.
/// Use `is_canonical_shape()` for exact canonical filtering.
pub fn is_p2_core_capability(cap: &ShapeCapability) -> bool {
    use ShapeCapabilityKind::*;
    matches!(cap.kind, P2CoreSimple | P2CoreSkipWs | P2CoreAtoi | P2MidParseNumber)
}

/// Phase 44: Check if capability is supported by Normalized dev
pub fn is_supported_by_normalized(cap: &ShapeCapability) -> bool {
    // Currently same as P2-Core family
    is_p2_core_capability(cap)
}

/// canonical（常時 Normalized 経路を通す）対象。
/// Phase 46: Extract canonical shapes from JoinModule.
///
/// Canonical set (P2-Core + P2-Mid):
/// - Pattern2Mini, skip_ws mini/real, atoi mini/real, parse_number real
///
/// These shapes ALWAYS use Normalized→MIR(direct) regardless of mode.
/// P3/P4 patterns are NOT canonical (future NORM-P3/NORM-P4 phases).
pub(crate) fn canonical_shapes(module: &JoinModule) -> Vec<NormalizedDevShape> {
    let shapes: Vec<_> = detect_shapes(module)
        .into_iter()
        .filter(|s| is_canonical_shape(s))
        .collect();
    log_shapes("canonical", &shapes);
    shapes
}

#[allow(dead_code)]
pub(crate) fn is_direct_supported(module: &JoinModule) -> bool {
    !detect_shapes(module).is_empty()
}

fn detect_shapes(module: &JoinModule) -> Vec<NormalizedDevShape> {
    let mut shapes: Vec<_> = SHAPE_DETECTORS
        .iter()
        .filter_map(|(shape, detector)| if detector(module) { Some(*shape) } else { None })
        .collect();

    // Pattern1 は「最小の後方互換」なので、より具体的な shape が見つかった場合は外しておく。
    if shapes.len() > 1 {
        shapes.retain(|s| *s != NormalizedDevShape::Pattern1Mini);
    }

    shapes
}

// --- 判定ロジック（共通） ---
mod detectors {
    use super::*;

    pub(super) fn is_pattern1_mini(module: &JoinModule) -> bool {
        module.is_structured() && find_loop_step(module).is_some()
    }

    pub(super) fn is_pattern2_mini(module: &JoinModule) -> bool {
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }
        let loop_func = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };
        if !(1..=3).contains(&loop_func.params.len()) {
            return false;
        }

        let has_cond_jump = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Jump { cond: Some(_), .. }));
        let has_tail_call = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        has_cond_jump && has_tail_call
    }

    pub(super) fn is_jsonparser_skip_ws_mini(module: &JoinModule) -> bool {
        is_pattern2_mini(module)
            && module
                .functions
                .values()
                .any(|f| f.name == "jsonparser_skip_ws_mini")
    }

    pub(crate) fn is_jsonparser_skip_ws_real(module: &JoinModule) -> bool {
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }
        let loop_func = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };
        if !(2..=6).contains(&loop_func.params.len()) {
            return false;
        }

        let has_cond_jump = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Jump { cond: Some(_), .. }));
        let has_tail_call = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        has_cond_jump
            && has_tail_call
            && module
                .functions
                .values()
                .any(|f| f.name == "jsonparser_skip_ws_real")
    }

    pub(crate) fn is_jsonparser_atoi_mini(module: &JoinModule) -> bool {
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }
        let loop_func = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };
        if !(3..=8).contains(&loop_func.params.len()) {
            return false;
        }

        let has_cond_jump = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Jump { cond: Some(_), .. }));
        let has_tail_call = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        has_cond_jump
            && has_tail_call
            && module
                .functions
                .values()
                .any(|f| f.name == "jsonparser_atoi_mini")
    }

    pub(crate) fn is_jsonparser_atoi_real(module: &JoinModule) -> bool {
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }
        let loop_func = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };
        if !(3..=10).contains(&loop_func.params.len()) {
            return false;
        }

        let has_cond_jump = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Jump { cond: Some(_), .. }));
        let has_tail_call = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        has_cond_jump
            && has_tail_call
            && module
                .functions
                .values()
                .any(|f| f.name == "jsonparser_atoi_real")
    }

    pub(crate) fn is_jsonparser_parse_number_real(module: &JoinModule) -> bool {
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }
        let loop_func = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };
        if !(3..=12).contains(&loop_func.params.len()) {
            return false;
        }

        let has_cond_jump = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Jump { cond: Some(_), .. }));
        let has_tail_call = loop_func
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        has_cond_jump
            && has_tail_call
            && module
                .functions
                .values()
                .any(|f| f.name == "jsonparser_parse_number_real")
    }

    /// Phase 47-A: Check if module matches Pattern3 if-sum minimal shape
    pub(crate) fn is_pattern3_if_sum_minimal(module: &JoinModule) -> bool {
        // Structure-based detection (avoid name-based heuristics)

        // Must have exactly 3 functions: main, loop_step, k_exit
        if !module.is_structured() || module.functions.len() != 3 {
            return false;
        }

        // Find loop_step function
        let loop_step = match find_loop_step(module) {
            Some(f) => f,
            None => return false,
        };

        // P3 characteristics:
        // - Has Compare instruction (loop condition)
        // - Has Select instruction (conditional carrier update: if-then-else)
        // - Has tail call (Call with k_next: None)

        let has_compare = loop_step.body.iter().any(|inst| {
            matches!(
                inst,
                JoinInst::Compute(crate::mir::join_ir::MirLikeInst::Compare { .. })
            )
        });

        // Phase 220: Select can be either JoinInst::Select or Compute(MirLikeInst::Select)
        let has_select = loop_step.body.iter().any(|inst| match inst {
            JoinInst::Select { .. } => true,
            JoinInst::Compute(mir_inst) => matches!(
                mir_inst,
                crate::mir::join_ir::MirLikeInst::Select { .. }
            ),
            _ => false,
        });

        let has_tail_call = loop_step
            .body
            .iter()
            .any(|inst| matches!(inst, JoinInst::Call { k_next: None, .. }));

        // P3 minimal has 2-4 params (i, sum, possibly n)
        let reasonable_param_count = (2..=4).contains(&loop_step.params.len());

        has_compare && has_select && has_tail_call && reasonable_param_count
    }

    pub(super) fn find_loop_step(module: &JoinModule) -> Option<&JoinFunction> {
        module
            .functions
            .values()
            .find(|f| f.name == "loop_step")
            .or_else(|| module.functions.get(&JoinFuncId::new(1)))
    }
}

fn log_shapes(tag: &str, shapes: &[NormalizedDevShape]) {
    if shapes.is_empty() {
        return;
    }
    if dev_env::normalized_dev_logs_enabled() && joinir_dev_enabled() {
        eprintln!("[joinir/normalized-dev/shape] {}: {:?}", tag, shapes);
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[cfg(feature = "normalized_dev")]
    #[test]
    fn test_detect_pattern3_if_sum_minimal_shape() {
        use crate::mir::join_ir::normalized::fixtures::build_pattern3_if_sum_min_structured_for_normalized_dev;

        let module = build_pattern3_if_sum_min_structured_for_normalized_dev();

        // Should detect Pattern3IfSumMinimal shape
        assert!(
            detectors::is_pattern3_if_sum_minimal(&module),
            "pattern3_if_sum_minimal fixture should be detected"
        );

        let shapes = detect_shapes(&module);
        assert!(
            shapes.contains(&NormalizedDevShape::Pattern3IfSumMinimal),
            "detect_shapes() should include Pattern3IfSumMinimal, got: {:?}",
            shapes
        );
    }
}