紙の注文書・FAX・手書き日報を
「指示文（プロンプト）入力ゼロ」でデジタル台帳へ自動変換する仕組み

#![forbid(unsafe_code)]

/// Normalized 2D bounding box in [0, 1000] coordinate space for UI crop highlighting.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct NormalizedBBox {
    pub x0: u16,
    pub y0: u16,
    pub x1: u16,
    pub y1: u16,
}

impl NormalizedBBox {
    #[inline]
    pub const fn is_valid(self) -> bool {
        self.x0 < self.x1 && self.y0 < self.y1 && self.x1 <= 1000 && self.y1 <= 1000
    }
}

/// Extracted order line item with calibrated confidence in permille (0..=1000, where 960 == 96.0%).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ExtractedOrderLine<'a> {
    pub raw_item_text: &'a str,
    pub resolved_sku: Option<&'a str>,
    pub quantity: i64,
    pub unit_price_yen: i64,
    pub stated_line_amount_yen: i64,
    pub confidence_permille: u16,
    pub source_bbox: NormalizedBBox,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum LineReviewReason {
    InvalidBoundingBox { line_index: usize },
    NonPositiveQuantityOrPrice { line_index: usize },
    UnresolvedSkuAlias { line_index: usize },
    LowOcrConfidence { line_index: usize, confidence_permille: u16 },
    LineArithmeticMismatch { line_index: usize, expected_yen: i64, stated_yen: i64 },
    SubtotalMismatch { computed_subtotal_yen: i64, stated_subtotal_yen: i64 },
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub enum OrderGateDecision {
    /// All lines passed deterministic arithmetic & confidence gates; ready for 1-click commit.
    ReadyForInstantCommit { verified_subtotal_yen: i64 },
    /// Escalate only the flagged fields to the 3-item human confirmation UI.
    RequiresTargetedHumanReview {
        computed_subtotal_yen: i64,
        reasons: Vec<LineReviewReason>,
    },
}

/// Minimum calibrated confidence permille required for zero-touch field acceptance (96.0%).
pub const MIN_AUTO_CONFIDENCE_PERMILLE: u16 = 960;

/// Evaluates an extracted FAX/PDF order sheet using exact 64-bit integer arithmetic
/// and calibrated confidence thresholds.
pub fn evaluate_order_sheet(
    lines: &[ExtractedOrderLine<'_>],
    stated_sheet_subtotal_yen: i64,
) -> OrderGateDecision {
    let mut reasons = Vec::new();
    let mut computed_subtotal_yen: i64 = 0;

    for (idx, line) in lines.iter().enumerate() {
        if !line.source_bbox.is_valid() {
            reasons.push(LineReviewReason::InvalidBoundingBox { line_index: idx });
        }
        if line.quantity <= 0 || line.unit_price_yen < 0 {
            reasons.push(LineReviewReason::NonPositiveQuantityOrPrice { line_index: idx });
        }
        if line.resolved_sku.is_none() {
            reasons.push(LineReviewReason::UnresolvedSkuAlias { line_index: idx });
        }
        if line.confidence_permille < MIN_AUTO_CONFIDENCE_PERMILLE {
            reasons.push(LineReviewReason::LowOcrConfidence {
                line_index: idx,
                confidence_permille: line.confidence_permille,
            });
        }

        let expected_line_yen = line
            .quantity
            .checked_mul(line.unit_price_yen)
            .unwrap_or(i64::MAX);
        if expected_line_yen != line.stated_line_amount_yen {
            reasons.push(LineReviewReason::LineArithmeticMismatch {
                line_index: idx,
                expected_yen: expected_line_yen,
                stated_yen: line.stated_line_amount_yen,
            });
        }
        computed_subtotal_yen = computed_subtotal_yen.saturating_add(expected_line_yen);
    }

    if computed_subtotal_yen != stated_sheet_subtotal_yen {
        reasons.push(LineReviewReason::SubtotalMismatch {
            computed_subtotal_yen,
            stated_subtotal_yen: stated_sheet_subtotal_yen,
        });
    }

    if reasons.is_empty() {
        OrderGateDecision::ReadyForInstantCommit {
            verified_subtotal_yen: computed_subtotal_yen,
        }
    } else {
        OrderGateDecision::RequiresTargetedHumanReview {
            computed_subtotal_yen,
            reasons,
        }
    }
}