package store

import (
	"context"
	"database/sql"
	"fmt"
)

// User is one geniusrun account, bound 1:1 to an OIDC subject. Every
// synced/classified dataset (profile, workout kinds, activities, sync
// state) is scoped to exactly one User -- see
// docs/superpowers/specs/2026-07-25-per-user-profile-design.md.
type User struct {
	ID        int64
	OIDCSub   string
	Name      string
	CreatedAt string
}

// GetUserBySub looks up a user by their OIDC subject -- the only lookup key
// the session-resolution middleware ever uses.
func (db *DB) GetUserBySub(ctx context.Context, oidcSub string) (User, bool, error) {
	var u User
	err := db.QueryRowContext(ctx, `SELECT id, oidc_sub, name, created_at FROM users WHERE oidc_sub = ?`, oidcSub).
		Scan(&u.ID, &u.OIDCSub, &u.Name, &u.CreatedAt)
	if err == sql.ErrNoRows {
		return User{}, false, nil
	}
	if err != nil {
		return User{}, false, fmt.Errorf("get user by sub: %w", err)
	}
	return u, true, nil
}

// neverMatchRule is the placeholder every fresh install's rule-engine kinds
// start with -- every activity lands in needs_review until the user tunes
// real rules.
const neverMatchRule = `{"match":"all","conditions":[{"metric":"distance_meters","op":"<","value":0}]}`

// defaultWorkoutKindSeeds mirrors the 8 kinds migrations 0004/0007 seed for
// a fresh install, so a newly-provisioned user starts with the same
// taxonomy instead of an empty one.
var defaultWorkoutKindSeeds = []WorkoutKind{
	{Name: "Easy", Color: "#22c55e", RuleJSON: neverMatchRule, Priority: 80, IsActive: true},
	{Name: "Long", Color: "#3b82f6", RuleJSON: neverMatchRule, Priority: 70, IsActive: true},
	{Name: "60' Threshold", Color: "#f59e0b", RuleJSON: neverMatchRule, Priority: 60, IsActive: true},
	{Name: "30' Threshold", Color: "#f59e0b", RuleJSON: neverMatchRule, Priority: 50, IsActive: true},
	{Name: "Tempo", Color: "#eab308", RuleJSON: neverMatchRule, Priority: 40, IsActive: true},
	{Name: "Intervals", Color: "#ef4444", RuleJSON: neverMatchRule, Priority: 30, IsActive: true},
	{Name: "MAS Test", Color: "#a855f7", RuleJSON: neverMatchRule, Priority: 20, IsActive: true},
	{Name: "Race", Color: "#dc2626", RuleJSON: `{"match":"all","conditions":[{"metric":"is_race","op":"==","value":true}]}`, Priority: 10, IsActive: true},
}

// ProvisionUser creates a brand-new geniusrun account for an OIDC subject:
// the users row, a default profile (name defaulted to displayName), the 8
// default workout kinds (with their paired workout_type_paces rows), and an
// initial sync_state row -- all in one transaction, so a partially
// provisioned user is never observable.
func (db *DB) ProvisionUser(ctx context.Context, oidcSub, name string) (int64, error) {
	tx, err := db.BeginTx(ctx, nil)
	if err != nil {
		return 0, fmt.Errorf("begin provision user tx: %w", err)
	}
	defer tx.Rollback()

	res, err := tx.ExecContext(ctx, `INSERT INTO users (oidc_sub, name) VALUES (?, ?)`, oidcSub, name)
	if err != nil {
		return 0, fmt.Errorf("create user %q: %w", oidcSub, err)
	}
	userID, err := res.LastInsertId()
	if err != nil {
		return 0, err
	}

	if _, err := tx.ExecContext(ctx, `INSERT INTO profiles (user_id) VALUES (?)`, userID); err != nil {
		return 0, fmt.Errorf("create profile for user %d: %w", userID, err)
	}

	for _, k := range defaultWorkoutKindSeeds {
		res, err := tx.ExecContext(ctx, `
			INSERT INTO workout_kinds (user_id, name, description, color, rule_json, priority, is_active)
			VALUES (?,?,?,?,?,?,?)`,
			userID, k.Name, k.Description, k.Color, k.RuleJSON, k.Priority, k.IsActive)
		if err != nil {
			return 0, fmt.Errorf("seed workout kind %q for user %d: %w", k.Name, userID, err)
		}
		kindID, err := res.LastInsertId()
		if err != nil {
			return 0, err
		}
		if _, err := tx.ExecContext(ctx, `INSERT INTO workout_type_paces (workout_kind_id) VALUES (?)`, kindID); err != nil {
			return 0, fmt.Errorf("seed workout type pace for kind %d: %w", kindID, err)
		}
	}

	if _, err := tx.ExecContext(ctx, `INSERT INTO sync_state (user_id, earliest_synced_date, backfill_complete) VALUES (?, NULL, 0)`, userID); err != nil {
		return 0, fmt.Errorf("create sync state for user %d: %w", userID, err)
	}

	return userID, tx.Commit()
}

// DeleteUser permanently deletes userID's account. Every row that belongs
// to it -- profile, workout kinds (and their paces), activities (and their
// laps/samples/kind_assignments), sync_state, and sync_runs -- cascades
// away via the ON DELETE CASCADE foreign keys in schema.sql, so this is a
// single statement rather than per-table deletes. Irreversible; the API
// layer gates this behind a UI confirmation (see
// docs/superpowers/specs/2026-07-26-profile-deletion-design.md).
func (db *DB) DeleteUser(ctx context.Context, userID int64) error {
	if _, err := db.ExecContext(ctx, `DELETE FROM users WHERE id = ?`, userID); err != nil {
		return fmt.Errorf("delete user %d: %w", userID, err)
	}
	return nil
}

// UpdateUserName renames userID's account -- the single human-facing name
// (shown in the header and session info), editable from the Profile page.
func (db *DB) UpdateUserName(ctx context.Context, userID int64, name string) error {
	if _, err := db.ExecContext(ctx, `UPDATE users SET name = ? WHERE id = ?`, name, userID); err != nil {
		return fmt.Errorf("update name for user %d: %w", userID, err)
	}
	return nil
}