from collections import Counter
from dateutil.relativedelta import relativedelta
from odoo import api, fields, models


def _float_to_time(f):
    if not f:
        return "—"
    h = int(f)
    m = int(round((f % 1) * 60))
    return f"{h:02d}:{m:02d}"


class DanceDashboard(models.Model):
    _name = "dance.dashboard"
    _description = "Dance Dashboard"

    name = fields.Char(default="Dance Dashboard", required=True)

    # ── Computed fields kept for legacy form view ──────────────────────────────
    total_students = fields.Integer(compute="_compute_kpis")
    active_batches = fields.Integer(compute="_compute_kpis")
    active_enrollments = fields.Integer(compute="_compute_kpis")
    dropped_enrollments = fields.Integer(compute="_compute_kpis")
    monthly_revenue = fields.Monetary(compute="_compute_kpis", currency_field="currency_id")
    pending_fees = fields.Monetary(compute="_compute_kpis", currency_field="currency_id")
    currency_id = fields.Many2one("res.currency", compute="_compute_kpis")

    @api.depends_context("company")
    def _compute_kpis(self):
        today = fields.Date.context_today(self)
        month_start = today.replace(day=1)
        company = self.env.company
        invoice_model = self.env["account.move"]

        paid_this_month = invoice_model.search([
            ("move_type", "=", "out_invoice"),
            ("state", "=", "posted"),
            ("payment_state", "=", "paid"),
            ("dance_student_id", "!=", False),
            ("invoice_date", ">=", month_start),
            ("invoice_date", "<=", today),
            ("company_id", "=", company.id),
        ])
        pending_invoices = invoice_model.search([
            ("move_type", "=", "out_invoice"),
            ("state", "=", "posted"),
            ("payment_state", "in", ["not_paid", "partial"]),
            ("dance_student_id", "!=", False),
            ("company_id", "=", company.id),
        ])

        values = {
            "total_students": self.env["res.partner"].search_count([("is_student", "=", True)]),
            "active_batches": self.env["dance.batch"].search_count([("status", "=", "active")]),
            "active_enrollments": self.env["dance.enrollment"].search_count([("status", "=", "active")]),
            "dropped_enrollments": self.env["dance.enrollment"].search_count([("status", "=", "dropped")]),
            "monthly_revenue": sum(paid_this_month.mapped("amount_total")),
            "pending_fees": sum(pending_invoices.mapped("amount_residual")),
            "currency_id": company.currency_id.id,
        }
        for dashboard in self:
            dashboard.update(values)

    # ── Client-action data endpoint ────────────────────────────────────────────

    @api.model
    def get_dashboard_data(self):
        today = fields.Date.context_today(self)
        company = self.env.company
        invoice_model = self.env["account.move"]

        # ── Core KPIs ──────────────────────────────────────────────────────────
        month_start = today.replace(day=1)

        paid_this_month = invoice_model.search([
            ("move_type", "=", "out_invoice"),
            ("state", "=", "posted"),
            ("payment_state", "=", "paid"),
            ("dance_student_id", "!=", False),
            ("invoice_date", ">=", month_start),
            ("invoice_date", "<=", today),
            ("company_id", "=", company.id),
        ])
        pending_invoices = invoice_model.search([
            ("move_type", "=", "out_invoice"),
            ("state", "=", "posted"),
            ("payment_state", "in", ["not_paid", "partial"]),
            ("dance_student_id", "!=", False),
            ("company_id", "=", company.id),
        ])

        monthly_revenue = sum(paid_this_month.mapped("amount_total"))
        pending_fees = sum(pending_invoices.mapped("amount_residual"))
        currency = company.currency_id

        def fmt(amount):
            sym = currency.symbol or "$"
            if amount >= 1_000_000:
                return f"{sym}{amount / 1_000_000:.1f}M"
            if amount >= 1_000:
                return f"{sym}{amount / 1_000:.1f}K"
            return f"{sym}{amount:,.0f}"

        sessions_today = self.env["dance.session"].search_count([
            ("date", "=", today),
            ("status", "!=", "cancelled"),
        ])

        kpis = {
            "total_students": self.env["res.partner"].search_count([("is_student", "=", True)]),
            "active_batches": self.env["dance.batch"].search_count([("status", "=", "active")]),
            "active_enrollments": self.env["dance.enrollment"].search_count([("status", "=", "active")]),
            "dropped_enrollments": self.env["dance.enrollment"].search_count([("status", "=", "dropped")]),
            "sessions_today": sessions_today,
            "monthly_revenue": monthly_revenue,
            "monthly_revenue_fmt": fmt(monthly_revenue),
            "pending_fees": pending_fees,
            "pending_fees_fmt": fmt(pending_fees),
            "currency_symbol": currency.symbol or "$",
        }

        return {
            "kpis": kpis,
            "revenue_chart": self._revenue_last_6_months(today, company, invoice_model),
            "attendance_chart": self._attendance_last_30_days(today),
            "style_distribution": self._style_distribution(),
            "sessions": self._today_sessions(today),
        }

    def _revenue_last_6_months(self, today, company, invoice_model):
        labels, data = [], []
        for i in range(5, -1, -1):
            month_date = today - relativedelta(months=i)
            ms = month_date.replace(day=1)
            me = (ms + relativedelta(months=1)) - relativedelta(days=1)
            if i == 0:
                me = today
            labels.append(ms.strftime("%b '%y"))
            paid = invoice_model.search([
                ("move_type", "=", "out_invoice"),
                ("state", "=", "posted"),
                ("payment_state", "=", "paid"),
                ("dance_student_id", "!=", False),
                ("invoice_date", ">=", ms),
                ("invoice_date", "<=", me),
                ("company_id", "=", company.id),
            ])
            data.append(round(sum(paid.mapped("amount_total")), 2))
        return {"labels": labels, "data": data}

    def _attendance_last_30_days(self, today):
        cutoff = today - relativedelta(days=30)
        att = self.env["dance.attendance"].search([
            ("session_id.date", ">=", cutoff),
            ("session_id.date", "<=", today),
        ])
        statuses = att.mapped("status")
        return {
            "present": statuses.count("present"),
            "absent": statuses.count("absent"),
            "late": statuses.count("late"),
        }

    def _style_distribution(self):
        enrollments = self.env["dance.enrollment"].search([("status", "=", "active")])
        style_field = self.env["dance.batch"]._fields.get("dance_style")
        style_map = dict(style_field.selection) if style_field else {}

        counts = Counter(
            e.batch_id.dance_style for e in enrollments if e.batch_id and e.batch_id.dance_style
        )
        if not counts:
            return {"labels": [], "data": []}

        # Sort by count desc for nicer chart
        sorted_items = sorted(counts.items(), key=lambda x: x[1], reverse=True)
        return {
            "labels": [style_map.get(code, code.title()) for code, _ in sorted_items],
            "data": [cnt for _, cnt in sorted_items],
        }

    def _today_sessions(self, today):
        sessions = self.env["dance.session"].search(
            [("date", "=", today)], order="start_time asc"
        )
        result = []
        for s in sessions:
            result.append({
                "id": s.id,
                "batch": s.batch_id.name if s.batch_id else "—",
                "time": f"{_float_to_time(s.start_time)} – {_float_to_time(s.end_time)}",
                "room": s.room or "—",
                "instructor": s.instructor_id.name if s.instructor_id else "—",
                "status": s.status,
            })
        return result

    # ── Navigation actions (legacy stat buttons) ───────────────────────────────

    def action_view_students(self):
        return {"type": "ir.actions.act_window", "name": "Students",
                "res_model": "res.partner", "domain": [("is_student", "=", True)],
                "view_mode": "tree,form", "context": {"default_is_student": True}}

    def action_view_batches(self):
        return {"type": "ir.actions.act_window", "name": "Active Batches",
                "res_model": "dance.batch", "domain": [("status", "=", "active")],
                "view_mode": "tree,form"}

    def action_view_enrollments(self):
        return {"type": "ir.actions.act_window", "name": "Active Enrollments",
                "res_model": "dance.enrollment", "domain": [("status", "=", "active")],
                "view_mode": "tree,form"}

    def action_view_dropped(self):
        return {"type": "ir.actions.act_window", "name": "Dropped Enrollments",
                "res_model": "dance.enrollment", "domain": [("status", "=", "dropped")],
                "view_mode": "tree,form"}

    def action_view_revenue(self):
        today = fields.Date.context_today(self)
        month_start = today.replace(day=1)
        return {"type": "ir.actions.act_window", "name": "Revenue This Month",
                "res_model": "account.move",
                "domain": [("move_type", "=", "out_invoice"), ("state", "=", "posted"),
                            ("payment_state", "=", "paid"), ("dance_student_id", "!=", False),
                            ("invoice_date", ">=", month_start), ("invoice_date", "<=", today)],
                "view_mode": "tree,form"}

    def action_view_pending(self):
        return {"type": "ir.actions.act_window", "name": "Outstanding Fees",
                "res_model": "account.move",
                "domain": [("move_type", "=", "out_invoice"), ("state", "=", "posted"),
                            ("payment_state", "in", ["not_paid", "partial"]),
                            ("dance_student_id", "!=", False)],
                "view_mode": "tree,form"}