function sameArrays(array1, array2) {
    if(array1.length != array2.length) return false;
    for(let e of array1) {
        if(!array2.includes(e)) return false;
    }
    return true;
}

async function championInfos(client, patch, championId) {
    const database = client.db("matches");
    const matches = database.collection(patch)
    const allMatches = matches.find()
    
    let winningMatches = 0;
    let losingMatches = 0;
    let totalMatches = 0;
    const runes = [];
    for await (let match of allMatches) {
        totalMatches += 1;
        for(let participant of match.info.participants) {
            if(participant.championId != championId) continue;
            
            if(participant.win)
                winningMatches += 1;
            else
                losingMatches += 1;

            const primaryStyle = participant.perks.styles[0].style
            const secondaryStyle = participant.perks.styles[1].style
            const selections = []
            for(let style of participant.perks.styles) {
                for(let perk of style.selections) {
                    selections.push(perk.perk)
                }
            }
            const gameRunes = {count:1, primaryStyle: primaryStyle, secondaryStyle: secondaryStyle, selections: selections};
            let addRunes = true;
            for(let rune of runes) {
                if(rune.primaryStyle == gameRunes.primaryStyle 
                    && rune.secondaryStyle == gameRunes.secondaryStyle
                    && sameArrays(rune.selections, gameRunes.selections)) {
                    rune.count++; addRunes = false; break;
                }
            }
            if(addRunes) runes.push(gameRunes)
            break;
        }
    }

    // Filter runes to keep 3 most played
    const maxes = [0, 0, 0] // 24, 2, 1 -> 18 > 1 -> 24, 2, 2 -> 18 > 2 -> 24, 24, 2
    const maxRunes = [null, null, null]
    for(let rune of runes) {
        let maxcount = 2;
        if(rune.count <= maxes[maxcount]) continue;
        
        while(maxcount > 0 && rune.count > maxes[maxcount]) {
            maxes[maxcount] = maxes[maxcount - 1];
            maxRunes[maxcount] = maxRunes[maxcount - 1];
            maxcount--;
        }

        rune.pickrate = rune.count / (winningMatches + losingMatches)
        if(rune.count <= maxes[maxcount]) maxcount++;
        maxes[maxcount] = rune.count
        maxRunes[maxcount] = rune
    }

    return {id: championId,
            winrate:winningMatches / (winningMatches + losingMatches), 
            gameCount:(winningMatches + losingMatches),
            pickrate:(winningMatches + losingMatches)/totalMatches,
            runes: maxRunes.filter((x) => x != null)
            };
}

async function makeChampionStat(client, patch, championId) {
    const championInfo = await championInfos(client, patch, championId)
    const database = client.db("champions")
    const collection = database.collection(patch)
    await collection.updateOne({id: championInfo.id}, {$set: championInfo}, { upsert: true })
}

async function championList() {
    const response = await fetch("https://raw.communitydragon.org/latest/plugins/rcp-be-lol-game-data/global/default/v1/champion-summary.json");
    const list = await response.json()
    return list.slice(1)
}

async function makeChampionsStats(client, patch) {
    const list = await championList()
    console.log("Generating stats for " + list.length + " champions")
    let i = 0;
    for(let champion of list) {
        console.log("Entry " + i + "/" + list.length + " ...")
        await makeChampionStat(client, patch, champion.id)
        i += 1
    }

    const database = client.db("champions")
    const collection = database.collection(patch)
    await collection.createIndex({id:1})
}

module.exports = {makeChampionsStats}