package storage

import (
	"database/sql"
)

// The Siege, as gogobee pushes it.
//
// Same shape of thing as the roster and stored the same way: a whole snapshot
// that replaces whatever we had. Nothing here is an event — the *events*
// (siege_start / siege_win / siege_loss) come down the dispatch queue like any
// other fact. This is the thing that is currently true, which is the only kind
// of thing a health bar can honestly draw.

// SiegeDefender is one adventurer's standing in the current muster.
//
// Token is the same public roster token the board uses, so the defender board
// can link a name to their page — and it is EMPTY for an opted-out player. That
// is the whole opt-out story here: their damage still counts and still holds its
// rank (the town's effort is the town's), but there is no name and no link. Name
// carries gogobee's anonymised label in that case.
type SiegeDefender struct {
	Token       string `json:"token,omitempty"`
	Name        string `json:"name"`
	Level       int    `json:"level,omitempty"`
	Fights      int    `json:"fights"`
	Damage      int    `json:"damage"`
	FoughtToday bool   `json:"fought_today"`
}

// SiegePast is one closed-out Siege: what came, whether the town held, and who
// turned up most. The history is what makes the live bar mean anything.
type SiegePast struct {
	BossID      int64  `json:"boss_id"`
	BossName    string `json:"boss_name"`
	Tier        int    `json:"tier"`
	Outcome     string `json:"outcome"` // "defeated" | "survived"
	HPRemaining int    `json:"hp_remaining"`
	HPMax       int    `json:"hp_max"`
	Defenders   int    `json:"defenders"`
	MVP         string `json:"mvp,omitempty"`
	MVPFights   int    `json:"mvp_fights,omitempty"`
	EndedAt     int64  `json:"ended_at"`
}

// Siege is the complete war-room state: the live boss (if any), its muster, and
// every Siege that came before.
type Siege struct {
	Active     bool            `json:"active"`
	BossID     int64           `json:"boss_id,omitempty"`
	BossName   string          `json:"boss_name,omitempty"`
	Tier       int             `json:"tier,omitempty"`
	HPCurrent  int             `json:"hp_current"`
	HPMax      int             `json:"hp_max"`
	StartsAt   int64           `json:"starts_at,omitempty"`
	EndsAt     int64           `json:"ends_at,omitempty"`
	BoutsToday int             `json:"bouts_today"`
	Defenders  []SiegeDefender `json:"defenders,omitempty"`
	History    []SiegePast     `json:"history,omitempty"`
	SnapshotAt int64           `json:"snapshot_at"`
}

// ReplaceSiege swaps the whole war room for a new snapshot, in one transaction.
//
// Replace, never merge — for the same reason the roster does it. A defender who
// dropped out of the payload (opted out, deleted character) has to leave the
// board, and a Siege that ended has to stop showing a live bar. The transaction
// means a reader mid-swap sees the old Siege or the new one, never a boss with
// somebody else's muster under it.
//
// History is replaced too, not appended: gogobee is the authority on what has
// happened, and rebuilding from its list each tick means a corrected or purged
// row upstream can't leave a ghost siege on Pete forever.
func ReplaceSiege(s Siege, snapshotAt int64) error {
	tx, err := Get().Begin()
	if err != nil {
		return err
	}
	defer func() { _ = tx.Rollback() }()

	if _, err := tx.Exec(`DELETE FROM adventure_siege_defenders`); err != nil {
		return err
	}
	if _, err := tx.Exec(`DELETE FROM adventure_siege_history`); err != nil {
		return err
	}
	if _, err := tx.Exec(`
		INSERT INTO adventure_siege
		    (id, active, boss_id, boss_name, tier, hp_current, hp_max,
		     starts_at, ends_at, bouts_today, snapshot_at)
		VALUES (1, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
		ON CONFLICT(id) DO UPDATE SET
		    active = excluded.active, boss_id = excluded.boss_id,
		    boss_name = excluded.boss_name, tier = excluded.tier,
		    hp_current = excluded.hp_current, hp_max = excluded.hp_max,
		    starts_at = excluded.starts_at, ends_at = excluded.ends_at,
		    bouts_today = excluded.bouts_today, snapshot_at = excluded.snapshot_at`,
		s.Active, s.BossID, s.BossName, s.Tier, s.HPCurrent, s.HPMax,
		s.StartsAt, s.EndsAt, s.BoutsToday, snapshotAt); err != nil {
		return err
	}

	dstmt, err := tx.Prepare(`
		INSERT INTO adventure_siege_defenders
		    (pos, token, name, level, fights, damage, fought_today)
		VALUES (?, ?, ?, ?, ?, ?, ?)`)
	if err != nil {
		return err
	}
	defer dstmt.Close()
	for i, d := range s.Defenders {
		if _, err := dstmt.Exec(i, d.Token, d.Name, d.Level, d.Fights, d.Damage, d.FoughtToday); err != nil {
			return err
		}
	}

	hstmt, err := tx.Prepare(`
		INSERT INTO adventure_siege_history
		    (boss_id, boss_name, tier, outcome, hp_remaining, hp_max, defenders, mvp, mvp_fights, ended_at)
		VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`)
	if err != nil {
		return err
	}
	defer hstmt.Close()
	for _, h := range s.History {
		if _, err := hstmt.Exec(h.BossID, h.BossName, h.Tier, h.Outcome, h.HPRemaining,
			h.HPMax, h.Defenders, h.MVP, h.MVPFights, h.EndedAt); err != nil {
			return err
		}
	}
	return tx.Commit()
}

// LoadSiege returns the war room as last pushed. ok is false when gogobee has
// never pushed one at all — distinct from a pushed snapshot that says no Siege
// is camped, which is a real answer the page can render.
func LoadSiege() (Siege, bool, error) {
	var s Siege
	err := Get().QueryRow(`
		SELECT active, boss_id, boss_name, tier, hp_current, hp_max,
		       starts_at, ends_at, bouts_today, snapshot_at
		  FROM adventure_siege WHERE id = 1`).Scan(
		&s.Active, &s.BossID, &s.BossName, &s.Tier, &s.HPCurrent, &s.HPMax,
		&s.StartsAt, &s.EndsAt, &s.BoutsToday, &s.SnapshotAt)
	if err == sql.ErrNoRows {
		return Siege{}, false, nil
	}
	if err != nil {
		return Siege{}, false, err
	}

	drows, err := Get().Query(`
		SELECT token, name, level, fights, damage, fought_today
		  FROM adventure_siege_defenders ORDER BY pos ASC`)
	if err != nil {
		return s, true, err
	}
	defer drows.Close()
	for drows.Next() {
		var d SiegeDefender
		if err := drows.Scan(&d.Token, &d.Name, &d.Level, &d.Fights, &d.Damage, &d.FoughtToday); err != nil {
			return s, true, err
		}
		s.Defenders = append(s.Defenders, d)
	}
	if err := drows.Err(); err != nil {
		return s, true, err
	}

	hrows, err := Get().Query(`
		SELECT boss_id, boss_name, tier, outcome, hp_remaining, hp_max, defenders, mvp, mvp_fights, ended_at
		  FROM adventure_siege_history ORDER BY ended_at DESC, boss_id DESC`)
	if err != nil {
		return s, true, err
	}
	defer hrows.Close()
	for hrows.Next() {
		var h SiegePast
		if err := hrows.Scan(&h.BossID, &h.BossName, &h.Tier, &h.Outcome, &h.HPRemaining,
			&h.HPMax, &h.Defenders, &h.MVP, &h.MVPFights, &h.EndedAt); err != nil {
			return s, true, err
		}
		s.History = append(s.History, h)
	}
	return s, true, hrows.Err()
}